Docker Interview Questions and Answer Part – 28

What is a tag?

  • A reference to a registry
  • A reference to a repository
  • A reference to a specific image in a repository (Ans)
  • A reference to a specific image in a registry

Why are image layers read only?

  • So they can be compressed to reduce disk space
  • So we cannot write data inside a container
  • So they can be reused (Ans)

Which of the following container types doesn’t use namespace isolation?

  • Windows Server Container
  • Hyper-V Container (Ans)
  • Linux Container

Which of the following provides the initial container file system?

  • Volume(s)
  • Network drive
  • Host file system
  • Image (Ans)

Database data should be stored in:

  • Image layer
  • Volume (Ans)
  • Container Read/Write layer

In the past, to find software, we often used standalone web sites hosted by the creator of the software. Now, with Docker, how do we discover software?

  • Package Managers
  • Still use standalone web sites
  • Docker Engine
  • App Stores
  • Docker Hub (Ans)

In the past, we usually downloaded software in some sort of package to install it, for example a zip file or MSI file. Now, with Docker, how do we download

  • docker pull (Ans)
  • docker start
  • docker ps
  • docker download

When executing the command “docker pull microsoft/aspnet:4.6.2” what is the “microsoft” piece called?

  • User (Ans)
  • Image
  • Tag
  • Registry
  • Repository

On a computer, with either Linux or Windows installed, there’s a program that runs in a privileged mode that abstracts hardware and provides services to other
processes. What is this program?

  • User
  • User space
  • Kernel
  • Kernel space (Ans)
  • Application

After stopping a container, how do you run the application in it again?

  • docker run
  • docker start (Ans)
  • docker pull
  • docker restart

What’s the primary purpose of docker-compose?

  • Build containers, volumes, and networks (Ans)
  • Build images
  • Pull and push images
  • Cleanup containers.
  • Build containers

What does the -d in docker run -d nginx do?

  • Runs an attached container
  • Runs a container that will display output from the NGINX process in our console
  • Deletes the container when we stop the NGINX proces
  • Runs a detached container (Ans)

Where does the file system come from for a container?

  • From the machine the container is started on
  • From the image used to create the container (Ans)
  • From another special container called a parent container
  • From a remote network share hosted through Hyper-V

Which of the following allows you to share the host file system with a process in a container?

  • Network drive(s)
  • Image(s)
  • symlinks
  • Volume(s) (Ans)

How can you see the output of a process running in a detached container?

  • docker output
  • docker Is
  • docker run -it
  • docker exec -it
  • docker logs (Ans)

What does docker commit do?

  • Copies files into a container
  • Creates a container
  • Duplicates a container
  • Creates a snapshot of a running container for rolling back
  • Creates an image (Ans)

Which of the following is a good analogy for creating a container?

  • Installing software (Ans)
  • Downloading software
  • Extracting a zip file
  • Running software

How can processes in different containers talk to each other when using docker-compose?

  • Embedded DNS for Service Discovery (Ans)
  • Pass IP addresses in configuration files
  • Pass IP addresses in environment variables
  • Linking containers

What does an image contain?

  • The user space files (Ans)
  • Only an application’s files
  • Both the user and kernel space files
  • The kernel space files
  • The operating system

Removing an image is akin to what in traditional software management?

  • Deleting an installer file or zip file (Ans)
  • Uninstalling an application
  • Restarting an application
  • Stopping an application
Rajesh Kumar
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